Differences in 520/531 and 630/830 latitude cases

Putting aside processors, graphics, card/fingerprint readers, and warranty, etc; but moreso differences in the cases (apart from 520 being standard aspect)- I'm talking construction of the case and materials used specifically here.

Any of you dell guys seen both an example of 6 or 8 series and a 520/31? I am confused as to the case material. According to dell's spec sheets, they all have the magnesium frame, but reviews I have read mention that the case material on 520/31 is actually plastic- what does this mean exactly? Is it just that the palmrest is plastic, or is the entire case and lid plastic over magnesium?

Doesn't matter a whole lot to me, but mainly want to know if the d6/8 series are the same in this regard. The kiosks in the malls don't have examples of latitudes.

 

Well, maybe some of you who just have EITHER a 520/31 OR 6/830 can just fill in the blank by what material is where on the outside (regardless of what's underneath)-

is it poly or metal on...

palmrests-
bottom of case-
keyboard surround-
bezel-
lid-

And are hinges steel?



(edit- should have slipped a "1330!!!" in the title?)

 

Well I found part of the answer in case anyone else is interested:

http://www.dell.com/content/topics/...are_notebooks?c=us&cs=04&l=en&s=bsd&~tab=1#q2